There are four main types of melanoma, each with distinct appearance, growth patterns, and typical locations on the body. Superficial spreading melanoma is by far the most common, accounting for about 70% of all cases worldwide. The remaining types, including nodular melanoma, lentigo maligna melanoma, and acral lentiginous melanoma, differ in how fast they grow, who they tend to affect, and where they appear. Several rarer variants also exist, including amelanotic melanoma, mucosal melanoma, and desmoplastic melanoma.
Superficial Spreading Melanoma
Superficial spreading melanoma (SSM) is the most common subtype, making up roughly 70% of melanoma cases, and it’s especially prevalent among fair-skinned people. It typically starts as a flat or slightly raised spot with an uneven border, ranging from a few millimeters to several centimeters across. What makes it visually distinctive is its mix of colors: a single lesion can contain shades of brown, black, blue, red, gray, and white all at once.
SSM tends to grow outward across the skin surface before it begins growing downward into deeper layers. This horizontal growth phase can last months to years, which is actually an advantage. It gives you a longer window to notice changes and get the spot evaluated. SSM most commonly appears on the trunk in men and the legs in women. Of all the melanoma subtypes, SSM has the strongest association with a specific genetic mutation called BRAF, found in about 43% of BRAF-positive melanoma patients. This matters because targeted therapies exist for BRAF-driven tumors.
Nodular Melanoma
Nodular melanoma is the most aggressive of the common subtypes. Unlike superficial spreading melanoma, it skips the slow horizontal growth phase and pushes directly downward into the skin from the start. It can grow at a rate of 0.5 mm deeper per month, which means even short delays in diagnosis can significantly affect outcomes. Nodular melanoma accounts for 66% of all melanomas thicker than 3 mm, and that thickness is directly tied to how dangerous the cancer is.
The standard ABCDE rule (Asymmetry, Border, Color, Diameter, Evolution) that works well for spotting other melanomas often misses nodular melanoma because it can appear as a round, evenly colored bump. Dermatologists use an alternative set of criteria called the EFG rule instead: Elevated above the skin surface, Firm to the touch, and Growing progressively. Nodular melanomas often look like a dome-shaped bump that may be dark brown, black, or sometimes skin-colored. They commonly appear on the head, neck, and trunk, and they cause a disproportionately high number of melanoma deaths relative to how often they occur.
Lentigo Maligna Melanoma
Lentigo maligna melanoma develops on skin that has accumulated decades of sun damage, which is why it primarily affects older adults. The average age at diagnosis is 66 to 72 years, compared to 45 to 57 for other melanoma subtypes. It overwhelmingly favors the head and neck, with 86% of cases appearing in that region, and the cheek is the single most common site. When it does appear elsewhere, it tends to show up on the arms and legs of women and the back in men.
This type begins as lentigo maligna, a flat, irregularly shaped brown patch that stays within the outermost layer of skin (melanoma in situ). It grows very slowly, sometimes over years or even decades, before it potentially invades deeper tissue and becomes lentigo maligna melanoma. Because it starts as a flat, brown mark on sun-damaged skin in older people, it’s easily mistaken for an age spot or sunspot, which can delay diagnosis.
Acral Lentiginous Melanoma
Acral lentiginous melanoma (ALM) stands apart from other types because it develops on areas with little or no sun exposure: the palms of the hands, soles of the feet, and under the nails. It accounts for less than 3% of melanomas in white populations, but more than 50% of melanomas diagnosed in Black, Hispanic, and Asian individuals in the United States. This doesn’t mean these groups get melanoma more often overall. It means that when they do develop melanoma, it’s disproportionately likely to be this specific type.
ALM on the foot or under a nail can be particularly tricky to spot. A diagnostic framework called CUBED was developed specifically for foot lesions: Colored lesions (any part that isn’t normal skin color), Uncertain diagnosis, Bleeding from the foot or under the nail, Enlargement despite treatment, and Delay in healing beyond two months. Any of these signs warrants further evaluation.
When ALM develops under a fingernail or toenail, it’s called subungual melanoma. One of its hallmark warning signs is Hutchinson’s sign, where brown or black pigment extends from under the nail into the surrounding skin. This periungual pigment typically spreads across more than half the nail width and appears as discontinuous patches. A similar-looking phenomenon called pseudo-Hutchinson’s sign can occur with benign nail pigmentation, but it differs in key ways: the pigment has a clean linear border, fades near the base of the nail, and tends to disappear under magnification with a dermoscope.
Amelanotic Melanoma
Between 2% and 8% of all melanomas produce little to no visible pigment, making them some of the hardest to detect. These amelanotic melanomas can appear pink, red, skin-colored, or even white instead of the dark brown or black that most people associate with melanoma. They may look like a raised bump, a flat patch, or a sore that won’t heal. Because they lack the telltale dark pigment, they’re frequently mistaken for other skin conditions, from benign moles to non-melanoma skin cancers, which often leads to later diagnosis.
Amelanotic melanoma isn’t a separate biological category in the way the four main types are. Rather, any type of melanoma can present without pigment. Nodular melanomas are particularly likely to show up this way. If you have a new or changing bump on your skin that’s pink or flesh-colored and doesn’t resolve within a few weeks, it’s worth getting a professional look.
Rarer Types
Mucosal melanoma develops on the moist linings inside the body, including the mouth, nasal passages, throat, and genital or rectal areas. Because these locations aren’t visible during routine skin checks, mucosal melanomas are often found at a more advanced stage. They carry a different genetic profile than sun-related melanomas. Mutations in a gene called KIT are found in about 39% of mucosal melanomas, compared to much lower rates in standard skin melanomas. This distinction is clinically relevant because KIT-driven melanomas can respond to specific targeted treatments.
Desmoplastic melanoma is another uncommon variant, characterized by dense, fibrous tissue surrounding the cancer cells. It frequently appears on sun-damaged skin of the head and neck, and under a microscope it looks markedly different from typical melanoma, with spindle-shaped cells woven into collagen. This unusual appearance can fool even experienced pathologists, sometimes requiring special staining techniques to confirm the diagnosis. Desmoplastic melanoma tends to grow along nerves, which can cause numbness or tingling in the affected area.
How Thickness Determines Stage
Regardless of type, the single most important factor in melanoma staging is how deep the tumor extends into the skin, measured in millimeters. The key thresholds are 1.0 mm, 2.0 mm, and 4.0 mm. A melanoma 1 mm or thinner falls into the earliest invasive category. Between 1 and 2 mm is intermediate. Between 2 and 4 mm is higher risk. And anything thicker than 4 mm is the most advanced local stage. Whether the surface of the melanoma is ulcerated (broken down) also bumps it into a higher risk category at every thickness level.
These measurements directly translate to survival. When melanoma is localized, meaning it hasn’t spread beyond the original site, the five-year survival rate is 97.6%. Once it reaches nearby lymph nodes (regional spread), that drops to 60.3%. If it has spread to distant organs, the five-year survival rate is 16.2%. This is why catching melanoma early, while it’s still thin, makes such a dramatic difference. The type of melanoma matters, but the depth at diagnosis matters more.
Why Type Matters for Detection
Each melanoma type has its own detection challenge. Superficial spreading melanoma follows the classic warning signs most people learn about: asymmetry, irregular borders, multiple colors. Nodular melanoma doesn’t, which is why the EFG criteria (elevated, firm, growing) exist as a complement. Lentigo maligna melanoma mimics age spots on elderly skin. Acral lentiginous melanoma hides on soles and under nails, areas people rarely examine. And amelanotic melanoma lacks pigment entirely.
Knowing these different presentations matters because no single checklist catches every melanoma. A full skin check includes areas between toes, the soles of your feet, underneath nails, and mucous membranes. Any new or changing lesion that doesn’t fit neatly into “normal” deserves attention, whether it’s dark, light, flat, or raised.